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Hello people,

So the story is I looked at various guides how to rbg mod the sms2. Seemed easy enough, using caps and resistors etc, canibalised a scart multi input that I don't use anymore for the female socket.

So I followed the instructions and the best I have been able to get is a flickery rolling picture.
Im guessing from my limited electronic knowledge and trial and error, that there is something wrong with the sync, so I tried altering the resistor using a variety of potentiometers, the closest I got was a less flickery /rolling image before the image cut out all together.

I'm going nuts trying to figure this out. Any help will be appreciated.

I wanted this to be something fun to get my kids interested in electronics but its turning into a month long prolonged failure.

Are you sure you have ground connected?

ApolloBoy wrote

Are you sure you have ground connected?

I have checked all the connection to the scart socket, the grounds all go to ground on the Sega vid chip, I double checked my soldering even tried using a breadboard to duplicate the circuit to check I had working capacitors/ resistors, I even found a recommendation to pull the comp signal from pin11 so I tried that instead and got the same result.
In the end I pulled out the capacitors and resistors from the rbg and comp signal and the flickering image stayed the same, I tried adding variable resistors to the switching signal, the closest I get I a slightly less flickery picture before I end up dropping the image altogether.

Maybe I am destined to rf quality forever, or I have to find an SMS 1 somewhere and use my megadrive scart for it.

Are you getting your RGB signals from the VDP or the video encoder (which would be either the CXA1145 or MB3514)?

Author	Message
dazmania83 Joined: 17 Mar 2014 Posts: 2	almost rbg nodded a sms2 pal. Posted: Mon Mar 17, 2014 4:02 pm
dazmania83 Joined: 17 Mar 2014 Posts: 2	Hello people, So the story is I looked at various guides how to rbg mod the sms2. Seemed easy enough, using caps and resistors etc, canibalised a scart multi input that I don't use anymore for the female socket. So I followed the instructions and the best I have been able to get is a flickery rolling picture. Im guessing from my limited electronic knowledge and trial and error, that there is something wrong with the sync, so I tried altering the resistor using a variety of potentiometers, the closest I got was a less flickery /rolling image before the image cut out all together. I'm going nuts trying to figure this out. Any help will be appreciated. I wanted this to be something fun to get my kids interested in electronics but its turning into a month long prolonged failure.

ApolloBoy Joined: 30 Jan 2007 Posts: 322 Location: San Jose, CA	Posted: Mon Mar 17, 2014 6:29 pm
	Are you sure you have ground connected?

dazmania83 Joined: 17 Mar 2014 Posts: 2	Posted: Sat Apr 05, 2014 11:49 am
dazmania83 Joined: 17 Mar 2014 Posts: 2	ApolloBoy wrote Are you sure you have ground connected? I have checked all the connection to the scart socket, the grounds all go to ground on the Sega vid chip, I double checked my soldering even tried using a breadboard to duplicate the circuit to check I had working capacitors/ resistors, I even found a recommendation to pull the comp signal from pin11 so I tried that instead and got the same result. In the end I pulled out the capacitors and resistors from the rbg and comp signal and the flickering image stayed the same, I tried adding variable resistors to the switching signal, the closest I get I a slightly less flickery picture before I end up dropping the image altogether. Maybe I am destined to rf quality forever, or I have to find an SMS 1 somewhere and use my megadrive scart for it.

ApolloBoy Joined: 30 Jan 2007 Posts: 322 Location: San Jose, CA	Posted: Sun Apr 06, 2014 7:30 pm
	Are you getting your RGB signals from the VDP or the video encoder (which would be either the CXA1145 or MB3514)?

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